import turtle


t = turtle.Pen()
colors = ("yellow", "black", "yellow", "black", 'yellow')
t.width(6)
t.speed(6)
for i in range(6):
    t.penup()
    t.goto(0, -i * 10)
    t.pendown()
    t.color(colors[i % len(colors)])
    t.circle(12 + i * 12)
turtle.done()
